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Journal ArticleDOI

Skeletal electron counting in cluster species. Some generalisations and predictions

Kenneth Wade1
01 Jun 1972-Inorganic and Nuclear Chemistry Letters (Pergamon)-Vol. 8, Iss: 6, pp 559-562
About: This article is published in Inorganic and Nuclear Chemistry Letters.The article was published on 1972-06-01. It has received 145 citations till now. The article focuses on the topics: Electron counting & Cluster (physics).
Citations
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Book ChapterDOI
K. Wade1
TL;DR: In this paper, the borane-carborane structural pattern has been studied in a wide range of other compounds, including metal clusters, metal-hydrocarbon 7∼ complexes, and various neutral or charged hydrocarbons.
Abstract: Publisher Summary This is one of two articles in this volume that is concerned with the borane-carborane structural pattern. In the other, Williams has shown how the pattern reflects the coordination number preferences of the various atoms involved. The purpose of the present article is to note some bonding implications of the pattern, and to show its relevance to a wide range of other compounds, including metal clusters, metal-hydrocarbon 7∼ complexes, and various neutral or charged hydrocarbons. Boranes and carboranes may be regarded as cluster compounds in the sense defined by Cotton; they contain a finite group or skeleton of atoms held together entirely, mainly, or at least to a significant extent by bonding directly between those atoms, even though some other atoms may be associated intimately with the cluster. Examples of their structural pattern, however, can be found far beyond the confines of what is normally regarded as cluster chemistry, so this survey includes many systems not commonly referred to as clusters.

1,235 citations

Journal ArticleDOI
TL;DR: The greatest challenges to boron chemistry are still the synthesis of monophasic products in macroscopic quantities and in the form of single crystals, the unequivocal identification and determination of crystal structures, and a thorough understanding of their electronic situation.
Abstract: Many of the fundamental questions regarding the solid-state chemistry of boron are still unsolved, more than 200 years after its discovery. Recently, theoretical work on the existence and stability of known and new modifications of the element combined with high-pressure and high-temperature experiments have revealed new aspects. A lot has also happened over the last few years in the field of reactions between boron and main group elements. Binary compounds such as B(6)O, MgB(2), LiB(1-x), Na(3)B(20), and CaB(6) have caused much excitement, but the electron-precise, colorless boride carbides Li(2)B(12)C(2), LiB(13)C(2), and MgB(12)C(2) as well as the graphite analogue BeB(2)C(2) also deserve special attention. Physical properties such as hardness, superconductivity, neutron scattering length, and thermoelectricity have also made boron-rich compounds attractive to materials research and for applications. The greatest challenges to boron chemistry, however, are still the synthesis of monophasic products in macroscopic quantities and in the form of single crystals, the unequivocal identification and determination of crystal structures, and a thorough understanding of their electronic situation. Linked polyhedra are the dominating structural elements of the boron-rich compounds of the main group elements. In many cases, their structures can be derived from those that have been assigned to modifications of the element. Again, even these require a critical revision and discussion.

494 citations

Journal ArticleDOI
TL;DR: This Review presents the enormous progress that has been made in Zintl ion chemistry with an emphasis on syntheses, properties, structures, and theoretical treatments.
Abstract: For a long time, Zintl ions of Group 14 and 15 elements were considered to be remarkable species domiciled in solid-state chemistry that have unexpected stoichiometries and fascinating structures, but were of limited relevance The revival of Zintl ions was heralded by the observation that these species, preformed in solid-state Zintl phases, can be extracted from the lattice of the solids and dissolved in appropriate solvents, and thus become available as reactants and building blocks in solution chemistry The recent upsurge of research activity in this fast-growing field has now provided a rich plethora of new compounds, for example by substitution of these Zintl ions with organic groups and organometallic fragments, by oxidative coupling reactions leading to dimers, oligomers, or polymers, or by the inclusion of metal atoms under formation of endohedral cluster species and intermetalloid compounds; some of these species have good prospects in applications in materials science This Review presents the enormous progress that has been made in Zintl ion chemistry with an emphasis on syntheses, properties, structures, and theoretical treatments

377 citations

Book ChapterDOI
TL;DR: In the early 1950s, the structures of the more common boranes were still a matter of debate as discussed by the authors, and there remained strong tendencies to anticipate and interpret borane structures as having mildly nonconforming hydrocarbon structures.
Abstract: Publisher Summary In the early 1950s, the structures of the more common boranes were still a matter of debate. Although the hypothesis appeared to be a losing favor, there remained strong tendencies to anticipate and interpret borane structures as having mildly nonconforming hydrocarbon structures. As a number of boranes were verified as having polyhedral fragment configurations, the structural thread to hydrocarbon chemistry became weakened. Subsequently, many other boranes and carboranes were discovered, and a seemingly endless array of multifarious structural types had to be considered. Several schools of thought then arose. Members of one school treated each structure as a separate case, more or less succumbing to the thesis of an almost infinite variety of structural parameters. A second school took the view that although carborane structures were complex in nature, such structures could eventually be categorized or collated by improved theoretical treatments, which could be expected to become ever more accurate because of constantly improving computer systems.

234 citations

References
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Journal ArticleDOI
TL;DR: The skeletal structures of carboranes, the higher boranes and borane anions, and many transition-metal carbonyl cluster species are related to the number of skeletal bonding electron-pairs they contain this article.
Abstract: The skeletal structures of carboranes, the higher boranes and borane anions, and many transition-metal carbonyl cluster species are related to the number of skeletal bonding electron-pairs they contain; species with n skeletal atoms adopt closo-structures if held together by (n+ 1) pairs, nido-structures if held together by (n+ 2) pairs, and arachno-structures if held together by (n+ 3) pairs of skeletal bonding electrons.

701 citations

Book
01 Jan 1971

103 citations